Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 131 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.611 − 498 =
2. 2.682 − 399 =
3. 3.754 − 697 =
4. 4.833 − 699 =
5. 5.839 − 459 =
6. 6.974 − 198 =
7. 7.897 − 799 =
8. 8.669 − 237 =
9. 9.986 − 457 =
10. 10.498 − 139 =
11. 11.766 − 699 =
12. 12.793 − 378 =
13. 13.903 − 397 =
14. 14.834 − 798 =
15. 15.913 − 797 =
16. 16.977 − 539 =
17. 17.822 − 599 =
18. 18.643 − 379 =
19. 19.744 − 499 =
20. 20.533 − 498 =
21. 21.533 − 398 =
22. 22.339 − 198 =
23. 23.559 − 239 =
24. 24.544 − 527 =
25. 25.608 − 588 =
26. 26.253 − 197 =
27. 27.587 − 438 =
28. 28.947 − 699 =
29. 29.931 − 698 =
30. 30.408 − 329 =
31. 31.757 − 297 =
32. 32.627 − 498 =
33. 33.973 − 198 =
34. 34.926 − 698 =
35. 35.958 − 528 =
36. 36.651 − 558 =
37. 37.957 − 428 =
38. 38.563 − 529 =
39. 39.931 − 498 =
40. 40.605 − 298 =

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